Electroplating barrel



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United States Patent O 3,472,753 ELECTROPLATING BARREL Steve W.Wojtanek, Lake Forest, Ill., assignor to S'terlmg Systems Ltd., Chicago,Ill., a corporation of Illinois Filed July 7, 1966, Ser. No. 563,517Int. Cl. C23b 5/78 U.S. Cl. 204-213 8 Claims ABSTRACT F THE DISCLOSUREAn electroplating barrel formed of an open mesh fabric and a generallyrigid open grid structure coextensive with the fabric and bonded to theouter surface of the fabric. The fabric and grid are formed ofchemically inert materials.

This invention relates to improvements in electroplating barrels.

One of the objects of this invention is the provision of an improvedelectroplating barrel construction which is adapted for use in platingsmall articles, for example, electronic components and the like,although not necessarily limited in use to such articles.

Another object of this invention is the provision of a plating barrelhaving a sidewall formed of an inert fabric or mesh material and arigidifying or supporting outer structure permitting maximum circulationor transfer of electroplating solution into and out of the barrel toprovide a markedly higher electrical current input than in prior artdevices, thereby to effect a more rapid plating of parts thanheretofore.

A further object of this invention is the provision of a plating barrelof the foregoing character, which is adapted to be used for plating verysmall articles, some of which may have wire terminals, or sharp points,without the articles catching in the fabric mesh or projectingtherethrough, thereby avoiding any likelihood of burning of theprojecting ends by reason of the concentration of electrical current atsuch ends.

Still another object of this invention is the provision of ra platingbarrel of the foregoing character, in which the textured surface of thefabric mesh assists in elfecting tumbling of the parts being plated soas to achieve a more uniform plating on the surfaces of the parts thanheretofore.

Another object of this invention is the provision of a plating barrelwhich is simple in construction, economical to manufacture and highlyeticient in operation.

Other and further objects and advantages of this invention will becomeapparent from the following description when the same is considered inconnection with the accompanying drawings in which FIG. l is a frontelevational view showing an electroplating barrel embodying theinvention.

FIG. 2 is an end elevational view of the same.

FIG. 3 is a cross-sectional view, on an enlarged scale, takensubstantially on line 3 3 of FIG. 1.

FIG. 4 is a vertical cross-sectional View of a modified embodiment of myinvention.

FIG. 5 is a cross-sectional view taken substantially on line 5-5 of FIG.4.

FIGS. 6 and 7 are fragmentary cross-sectional views of other modifiedembodiments of my invention.

FIG. 8 is a cross-sectional View of a modified embodiment of myinvention, illustrating a plating barrel of the type adapted to beoperated at an oblique angle.

Referring to the drawings, particularly FIGS. 1 and 2, the numeral 10indicates generally a conventional electroplating barrel supporting androtating structure including a frame 11 having transverse members 12adapted to ice be rested on the upper edges of a tank containingelectroplating solution. The frame supports an electric motor 13 coupledto a drive pinion 14 which is operatively connected through an idlergear 16 to a ring gear 17 suitably fixed to the barrel 18. Thesupporting and driving structure for the barrel forms no part of thepresent invention.

The barrel 18 comprises a pair of end members 19 and 20 which may begenerally circular or hexagonal in shape and six generally rectangularpanels forming the hexagonal barrel wall. Five of the panels 21a, b, c,d and e are cemented to the end members 19 and 20 while one of thepanels 22 constitutes a removable closure member for an opening throughwhich the parts to be plated may be placed within the barrel and removedtherefrom.

It will be understood that the term barrel as used throughout thespecifications and claims includes any tubular form, whether polygonal,circular or other form in cross section.

Each of the panels 21 and 22 basically comprises a sheet of woven fabric23V of any suitable inert material which is unaffected by electroplatingsolutions. Such a fabric may be woven from polypropylene filaments andmay be of lany suitable size mesh depending upon the character of thearticles being plated so as to avoid penetration of any of the articlesinto the mesh openings.

Cemented or otherwise bonded to the outer surface of each fabric sheet23 is a supporting or rigidifying grid 24 which may also be formed of asuitable inert plastic material, such as acrylic resin. The grid 24 mayalso be formed of suitable metal or combination of plastic and metal.The grid 24, for example, may comprise a series of uniformly spacedlongitudinally extending strips intersected by correspondingly spacedtransversely extending strips. Thus, the openings defined by theintersecting grid strips are generally square, or rectangular asillustrated in FIGS. l and 2 of the drawings. However, it will beunderstood that any other suitable or desirable arrangement or patternof grid strips may be used. As seen clearly in FIG. 3, the grid stripshave substantial depth in relation to the dimensional area of the panelso that each panel is relatively rigid in structure. It will beunderstood that where the panel is increased in dimensional area it isdesirable to increase the depth of the strip in order to provide thenecessary rigidity and strength to the panel. It will also be understoodthat the grid preferably is molded as an integral unit so as to achievemaximum rigidity and economy in manufacture. The grid strips arerelatively thin in cross section so that the total area of contact withthe fabric sheet is maintained at a minimum to expose a maximum area ofthe fabric sheet for the passage of electroplating liuid and currenttherethrough, as will be hereinafter explained.

The fabric sheet provides a textured surface in the interior of thebarrel on which the articles to be plated are supported. The characterof the fabric which is arranged preferably with the warp of the fabricsheet extending longitudinally and parallel to the axis of rotation ofthe barrel, is such that when the barrel is rotating the edges of thearticles being plated engage against the warp strands of the fabricsheet. This substantially prevents the articles from sliding on thepanel until the particular panel in the rotation of the barrel reaches agenerally vertical position, at which time the articles are caused totumble into the lowermost portion of the barrel within theelectroplating solution. Such tumbling, of course, is extremelydesirable and results in uniform plating throughout the surfaces of thearticle. It will be apparent that in prior art barrels utilizing panelsformed of plastic sheets, such as Lucite, which have been drilled with aplurality of holes, the smooth surfaces of the plates do not assist inthe tumbling of the articles, and as a result, the articles merely slideas a mass from one panel to another as the barrel is caused to berotated. With the use of an electroplating barrel in accordance with myinvention a greater transfer of plating solution is effected than inprior art devices using perforated plastic panels, with the result thatspent plating solution is readily replaced wilh more active solution.Accordingly, substantially thirty percent more electrical current iscarried into the plating barrel resulting in a plating rate which isapproximately thirty per-cent greater than that accomplished withplating barrels of the prior art.

The adjacent longitudinal edges of the panels 21 may be provided withcooperating abutment elements 26, such as illustrated in FIG. 2, saidabutment elements being bonded to the longitudinal edges of said panelsand to each other. It will be understood that instead of bonding theabutment elements, other suitable means may be provided for detachablyconnecting adjacent panels.

Panels 21a and 21e are provided with longitudinally extending edgemembers 25a and 25h, respectively, shaped in cross-section substantiallyas illustrated in FIG. 3.

The closure panel 22 includes a frame having upper and lowerlongitudinal members 61 and 62, respectively, and side member 63. Theupper frame member 61 is grooved as illustrated to cooperate with theedge member 25a and the lower frame member 62 has a bevelled edge tocooperate with the edge member 25b. One or more spring clamps 64 arepivotally mounted on edge member 25b and serve to secure the closurepanel 22 in closed position. It will be understood that any suitablelocking means may be employed in place of that described.

While the panels 21 and 22 have been illustrated as being arranged inhexagonal arrangement to form the barrel wall, it will be understoodthat any other suitable form or shape may be employed and that insteadof using separate panels to form the barrel wall, both the fabric sheet23 and reinforcing grid 24 may be a single unit large enough to be bentinto suitable shape which may be polygonal, circular, or any other form,as desired.

The end members 19 and 20 may be formed similarly as the side walls,that is, with a fabric sheet bonded to a grid but, of course, suchmembers will be provided with conventional trunnions 31 which extendaxially from opposite sides of the barrel 18 and are received insuitable bearings carried in conventional hanger member 32 dependingfrom the frame 11. The trunions have axial bores through which arepassed the conventional electrical conductors 33, each of which has anelectrode or its inner end dangling into the barrel to engage thearticles being electroplated. The outer end of each conductor, ofcourse, is -connected to an electrical circuit.

While the use of end panels, as above described, is preferable, it willbe understood that such panels may also be formed of metal or plasticmembers which are perforated or inperforate and which are bonded orothenvise suitably secured to the end edges of the side panels 21constituting the wall of the barrel.

While the fabric sheet 23 in and of itself permits the transfer of ahigh volume of solution into the plating barrel, the character of thegrid structure 24 itself is such that the spaces defined by the gridstrips function as scoops or retaining pockets to scoop up platingsolution from the tank as the barrel is rotating, which solution, ofcourse, then drips into the interior of the plating barrel. Thus, anadditional quantity of plating solution is carried into the barrel overand beyond that which would normally pass through that portion of theside wall which is submerged in the plating solution at any particulartlme.

In the modified embodiment illustrated in FIGS 4 and 5, the barrel 35comprises a pair of end plates 36 which may be circular or of anysuitable shape. The end plates may be perforated or imperforate plasticor metal, or a fabric mesh supported on a grid, as hereinabovedescribed, and including trunions 37. A plurality of transverse bracemembers 38 are rigidly connected to the peripheral edge portions of theend plates 36 and are circumferentially spaced, as illustrated in FIG.5. The barrel wall comprises a web of fabric 39 of the type hereinabovedescribed, which is suitably secured to the end plates 36, the web beingin cylindrical form or in any suitable polygonal form desired. Cementedto the outer surface of the web 39 are a plurality of spaced arcuateribs 41 which are secured to the brace members by hanger elements 42, asshown. As illustrated in FIG. 5, the barrel wall is provided with a pairof longitudinally extending rigidifying members 43 which define anopening for the barrel. Said opening is closed by a removable panel 44which is also formed of the same fabric as the rest of the wall and isprovided with rigidifying elements and a suitable latching means forlocking the closure panel in position.

While only two arcuate ribs 41 are illustrated in FIG. 4, it will beunderstood that a greater number may be employed and that, in any event,a maximum area of fabric is exposed for the passage of plating solutiontherethrough.

In the modified embodiment illustrated in FIG. 6, the barrel wall 46 isformed of the same fabric as hereinabove described, and a plurality oflongitudinally extending ribs 47 spacedly arranged are cemented orbonded to the fabric. Said ribs are either integral with or suitablyconnected to bracing and rigidifying outer arcuate members 48. The ribs47 and fabric sheet 46 may be bonded to any of the types of end membershereinabove described.

In the modified embodiment illustrated in FIG. 7, the barrel wall 49 isformed of the same fabric, as hereinabove described, to the outersurface of which is cemented a plurality of longitudinally extendingribs 51 which are perforated intermediate their ends to receive cablesor cords 52 which secure the ribs together, in the manner illustrated.-It is, of course, understood that the end portions of the ribs 51 aresuitably anchored in end plates constituting the end members of thebarrel.

FIG. 8 illustrates modified embodiment in which the barrel is of thetype adapted to be operated at an oblique angle and has an open upperend. The barrel wall 54, similarly as in the other embodiments,comprises a sheet of woven fabric supported on a grid and may have anydesirable form. The bottom or lower end wall of the barrel may be formedlike the end members 19 and 20 hereinbefore described except that it isprovided with a suitable drive adapter 53 so that the barrel may bedriven 4by the conventional drive means illustrated.

It will be apparent from the foregoing that in each of the embodiments,hereinabove described, the use of the fabric sheet for the wall of thebarrel, together with the provision of exterior rigidifying memberssecured to the sheet affords a maximum passage of electroplatingsolution therethrough, with the result that plating may be accomplishedmore effectively and at more rapid rate than heretofore possible withthe use of corresponding prior art apparatus.

Various changes coming within the spirit of my invention may suggestthemselves to those skilled in the art; hence, I do not wish to belimited to the specific embodiments shown and described or usesmentioned, but intend the same to be merely exemplary, the scope of myinvention being limited only lby the appended claims.

I claim:

1. An electroplating barrel comprising a sidewall formed of an innerlayer of open mesh fabric having a fine opening size and an outersupporting layer consisting of a generally rigid grid structure having amultiplicity of relatively larger openings, the inner edge of the gridbeing coextensive with and bonded to the outer surface of said fabric,both of said layers being formed of chemically inert resinous materials.

2. The invention as defined in claim 1 in which the grid structure hassubstantial depth to provide scoops adapted to pick up plating solutionas the barrel is rotated in a plating tank.

3. The invention as defined in claim 1 in which the total area of thegrid elements in contact with the fabric layer is relatively small inrelation to the area of the fabric lla-yer so as to expose a maximumarea of fabric layer for the passage of plating fluid therethrough.

4. The invention as defined in claim 1 in which the barrel issubstantially hexagonal in cross Section.

5. The invention as defined in claim 1 in which the barrel issubstantially circular in cross section.

6. The invention as defined in claim 1 in which the warp strands of thefabric extend parallel to the longitudinal axis of the barrel.

7. The invention as defined in claim 1 in which the fabric is formed ofpolypropylene.

8. An electroplating barrel comprising a sidewall formed of a wovenfabric of chemically inert material adapted to pass electroplatingsolution but adapted to retain small articles to be electropliated witha minimum penetration of said articles into said fabric, a plurality ofsubstantially rigid spaced longitudinally extending strips, each bondedalong one edge to the outer surface of said fabric and a member passingsubstantially through all of said strips and extending circumferentiallyof said sidewall.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 631,015 10/1949Great Britain. 880,843 10/ 1961 Great Britain.

JOHN H. MACK, Primary Examiner 20 W. B. vANsIsE, Assistant Examiner U.S.Cl. X.R. 259--89'

